Photonic lattices-arrays of optical waveguides-are powerful platforms for simulating a range of phenomena, including topological phases. While probing dynamics is possible in these systems, by ...reinterpreting the propagation direction as time, accessing long timescales constitutes a severe experimental challenge. Here, we overcome this limitation by placing the photonic lattice in a cavity, which allows the optical state to evolve through the lattice multiple times. The accompanying detection method, which exploits a multi-pixel single-photon detector array, offers quasi-real time-resolved measurements after each round trip. We apply the state-recycling scheme to intriguing photonic lattices emulating Dirac fermions and Floquet topological phases. We also realise a synthetic pulsed electric field, which can be used to drive transport within photonic lattices. This work opens an exciting route towards the detection of long timescale effects in engineered photonic lattices and the realisation of hybrid analogue-digital simulators.
Deloitte's 2007 PCAOB Part II report identifies, among other issues, concerns related to the audit firm's quality controls with respect to auditing income tax accounts. We investigate whether ...Deloitte's actions to remediate the PCAOB's concerns are associated with changes to their clients' financial reporting for income taxes. We find that Deloitte's clients increased the reported valuation allowance on deferred tax assets and increased the reported reserve for uncertain tax benefits (UTBs) in response to increased auditor scrutiny over income tax accounts. Additionally, we find that in subsequent periods, Deloitte's clients report valuation allowances and UTB balances that are not significantly different than other annually inspected auditors, consistent with Deloitte changing the quality controls related to audits of income tax accounts after the failed remediation of the 2007 Part II report.
Aggressive Tax Planning and Labor Investments Traini, Simone; Goldman, Nathan C.; Lewellen, Christina M.
Journal of accounting, auditing & finance,
07/2024, Letnik:
39, Številka:
3
Journal Article
Recenzirano
We examine the association between aggressive tax planning and labor investment efficiency among U.S. firms. Labor is an important input to production that is material to many firms, and prior ...research suggests that inefficient labor investments can negatively affect future profitability and growth. We provide evidence that firms engaging in aggressive tax planning are associated with deviations from expected labor investments, which is indicative of labor investment inefficiency. We find that our results are concentrated in labor underinvestment, consistent with risks and uncertainties from aggressive tax planning making firms more cautious when investing. Our findings are strongest among firms with greater tax risk, higher labor costs, and weaker corporate governance. Our study contributes to the literature examining tax planning consequences by providing evidence that a tradeoff exists between aggressive tax planning and investments in labor. Therefore, our results suggest that managers should carefully consider the cash flow benefits of tax planning in conjunction with the potential effects of lower labor investments to ensure that the overall long-term effect of the tax strategy is value-increasing.
Ultracold atoms loaded into higher Bloch bands provide an elegant setting for realizing many-body quantum states that spontaneously break time-reversal symmetry through the formation of chiral ...orbital order. The applicability of this strategy remains nonetheless limited due to the finite lifetime of atoms in high-energy bands. Here we introduce an alternative framework, suitable for bosonic gases, which builds on assembling square plaquettes pierced by a π flux (half a magnetic-flux quantum). This setting is shown to be formally equivalent to an interacting bosonic gas loaded into p orbitals, and we explore the consequences of the resulting chiral orbital order, both for weak and strong on-site interactions. We demonstrate the emergence of a chiral superfluid vortex lattice, exhibiting a long-lived gapped collective mode that is characterized by local chiral currents. This chiral superfluid phase is shown to undergo a phase transition to a chiral Mott insulator for sufficiently strong interactions. Our work establishes coupled π-flux plaquettes as a practical route for the emergence of orbital order and chiral phases of matter.
Given that tax‐related critical audit matters (tax CAMs) were prevalent among accelerated filers (18.5% of observations) during the initial year of CAM disclosures, we examine whether an auditor's ...disclosure of tax CAMs is associated with variation in tax‐related financial reporting quality, tax avoidance, and tax‐related earnings management. Finding an association between tax CAMs and one of these tax outcomes would indicate that the new auditor reporting standard has indirectly affected investors. Examining the first year of CAM disclosures, we do not find that tax CAMs are associated with broad proxies of tax‐related audit or financial reporting quality (e.g., restatements, internal control weaknesses, comment letters) or tax avoidance (e.g., effective tax rates or book‐to‐tax differences). We do find that tax CAMs are associated with a modest increase in tax accrual quality, an increase in the reserve for unrecognized tax benefits, and a reduction in the likelihood of tax‐related earnings management. However, we do not find these tax CAM effects persist into the second year of CAM reporting. Our evidence is consistent with tax CAM disclosures having a modest but short‐lived effect on companies' reporting of tax accounts. Our findings should inform the PCAOB as they conduct their post‐implementation review of the new audit reporting standard.
Résumé
La divulgation des questions critiques de l’audit et des résultats liés à l’impôt
Les auteurs se penchent sur les questions critiques de l’audit liées à l’impôt (QCA fiscales), récurrentes chez les déposants utilisant le processus accéléré (représentant 18,5 % des observations), lors de la première année de divulgation des QCA. Ils examinent si l’information fournie par un auditeur sur les QCA fiscales est associée à une variation de la qualité de l’information financière relative à l’impôt, à l’évitement fiscal et à la gestion du résultat lié à l’impôt. Un lien entre les QCA fiscales et l’un de ces résultats fiscaux indiquerait que la nouvelle norme de rapport d’audit a eu un effet indirect sur les investisseurs. En examinant la première année de divulgation des QCA, les auteurs ne trouvent pas de lien entre les QCA fiscales et les indicateurs à large échelle de la qualité de l’audit ou de l’information financière relative à l’impôt (tels que les retraitements, les faiblesses du contrôle interne ou les lettres de commentaire), ni avec l’évitement fiscal (par exemple les taux d’imposition effectifs ou les écarts entre les valeurs fiscales et les valeurs comptables). Toutefois, ils trouvent un lien entre les QCA fiscales et une légère amélioration de la qualité des documents comptables, une augmentation de la réserve calculée en fonction des avantages fiscaux incertains et la réduction de la probabilité de la gestion du résultat lié à l’impôt. Cependant, ils n’observent pas que les effets liés aux QCA fiscales persistent lors de la deuxième année de divulgation des QCA. Les données recueillies par les auteurs indiquent que les divulgations des QCA fiscales ont un effet modeste, mais temporaire sur les rapports fiscaux des entreprises. Ces résultats devraient informer la Commission de surveillance de la comptabilité des sociétés cotées en bourse lors de son examen de suivi des nouvelles normes de rapport d’audit.
We present a proposal for a versatile cold-atom-based quantum simulator of relativistic fermionic theories and topological insulators in arbitrary dimensions. The setup consists of a spin-independent ...optical lattice that traps a collection of hyperfine states of the same alkaline atom, to which the different degrees of freedom of the field theory to be simulated are then mapped. We show that the combination of bi-chromatic optical lattices with Raman transitions can allow the engineering of a spin-dependent tunneling of the atoms between neighboring lattice sites. These assisted-hopping processes can be employed for the quantum simulation of various interesting models, ranging from non-interacting relativistic fermionic theories to topological insulators. We present a toolbox for the realization of different types of relativistic lattice fermions, which can then be exploited to synthesize a majority of phases in the periodic table of topological insulators.
Semimetals exhibiting nodal lines or nodal surfaces represent a novel class of topological states of matter. While conventional Weyl semimetals exhibit momentum-space Dirac monopoles, these more ...exotic semimetals can feature unusual topological defects that are analogous to extended monopoles. In this work, we describe a scheme by which nodal rings and nodal spheres can be realized in synthetic quantum matter through well-defined periodic-driving protocols. As a central result of our work, we characterize these nodal defects through the quantum metric, which is a gauge-invariant quantity associated with the geometry of quantum states. In the case of nodal rings, where the Berry curvature and conventional topological responses are absent, we show that the quantum metric provides an observable signature for these extended topological defects. Besides, we demonstrate that quantum-metric measurements could be exploited to directly detect the topological charge associated with a nodal sphere. We discuss possible experimental implementations of Floquet nodal defects in few-level atomic systems, paving the way for the exploration of Floquet-induced extended monopoles in quantum matter.
We reveal an intriguing manifestation of topology, which appears in the depletion rate of topological states of matter in response to an external drive. This phenomenon is presented by analyzing the ...response of a generic two-dimensional (2D) Chern insulator subjected to a circular time-periodic perturbation. Because of the system's chiral nature, the depletion rate is shown to depend on the orientation of the circular shake; taking the difference between the rates obtained from two opposite orientations of the drive, and integrating over a proper drive-frequency range, provides a direct measure of the topological Chern number (ν) of the populated band: This "differential integrated rate" is directly related to the strength of the driving field through the quantized coefficient η
= ν/
, where
= 2π
is Planck's constant. Contrary to the integer quantum Hall effect, this quantized response is found to be nonlinear with respect to the strength of the driving field, and it explicitly involves interband transitions. We investigate the possibility of probing this phenomenon in ultracold gases and highlight the crucial role played by edge states in this effect. We extend our results to 3D lattices, establishing a link between depletion rates and the nonlinear photogalvanic effect predicted for Weyl semimetals. The quantized circular dichroism revealed in this work designates depletion rate measurements as a universal probe for topological order in quantum matter.
We consider a spin-1/2 fermionic ladder with spin-orbit coupling and a perpendicular magnetic field, which shares important similarities with topological superconducting wires. We fully characterize ...the symmetry-protected topological phase of this ladder through the identification of fractionalized edge modes and non-trivial spin winding numbers. We propose an experimental scheme to engineer such a ladder system with cold atoms in optical lattices, and we present two protocols that can be used to extract the topological signatures from density and momentum-distribution measurements. We then consider the presence of interactions and discuss the effects of a contact on-site repulsion on the topological phase. We find that such interactions could enhance the extension of the topological phase in certain parameters regimes.
We investigate experimentally and theoretically a system ruled by an intricate interplay between topology, nonlinearity, and spontaneous symmetry breaking. The experiment is based on a two-mode ...coherently-driven optical resonator where photons interact through the Kerr nonlinearity. In presence of a phase defect, the modal structure acquires a synthetic Möbius topology enabling the realization of spontaneous symmetry breaking in inherently bias-free conditions without fine tuning of parameters. Rigorous statistical tests confirm the robustness of the underlying symmetry protection, which manifests itself by a periodic alternation of the modes reminiscent of period-doubling. This dynamic also confers long term stability to various localized structures including domain walls, solitons, and breathers. Our findings are supported by an effective Hamiltonian model and have relevance to other systems of interacting bosons and to the Floquet engineering of quantum matter. They could also be beneficial to the implementation of coherent Ising machines.
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